Of the 200 graduate students who were interviewed for a par time position at a call center, 110 had a bicycle, 25 had a master card and 130 had a mobile phone. 50 of them had both, a bicycle and a master card, 30 had both, a master card and a mobile phone and 60 had both, a bicycle and mobile phone and 10 had all three. How many candidates had none of the three?
How do you start a problem like this?
Draw a venn diagram:
Well....you can't if only 25 have a card.....how can 50 have a card and a bike?
Please proofread ....what should '25 had a mastercard ' be?